Generally speaking, train-surfing is a practice employed by crazy people who want to relive that scene from Octopussy by acting like complete idiots and running around on top of a train. However, it appears the incredibly careless and ridiculous "sport" might have found some new life in India, although its in a slightly different form.
As far as we can tell, this is essentially train-skitchin', which is slightly different than train-surfing because it takes place on the side of a train and not the top. For those who didn't spend the '90s watching the BBC, train surfing was a big deal in Europe in the '90s and resurfaced again in 2005. The practice is twofold: For one, its about skipping out on a ticket, but its also a bit of sport for ballsy types. Both are equally idiotic, and the participants certainly sign a death ticket of some kind, but that doesn't mean we can't stop watching the video over and over again.
We have to say, though, if this catches on (again), it's considerably more cool than planking or owling or whatever other dumb internet photo-op crap is going on. It's probably worthwhile to note that the original version of train surfing (on top of trains) resulted in a lot of deaths and the occasional lost limb. Perhaps, if things go well here, the resurgence will be more about hopping on the sides of trains while wearing a fez than dying.
As with all extreme sports, we have to caution you against trying this at home, but we're sure you're not that ballsy, right?